DMGR1/2112. The Campaign Sourcebook and Catacomb Guide.
This is actually a pretty good reference book for DMs. There is general advice on designing dungeons and indoor environments, and lots of stuff about running a game — practical table-manners type stuff, managing players, DMing style, all that. World-building and mapping and even suggestions on the hows and whys of in-game dungeon construction. It’s co-written by Janelle Jaquay, an icon of early D&D. So it has to be good, right?
It’s a little unusual for a 2e splatbook, in that some of the art is pretty bloody (pages 9, 33, and to a lesser degree 89), and there seem to be a couple of half-orcs among the PCs in various illustrations (pages 11 & 96 — though the guy on page 96 could be full orc).
There are great sample maps of various structures and environments that you might run as “dungeons” (understood here in the most basic sense as an boundaried adventuring environment, limiting where you can go). A pyramid, caverns, a temple, that sort of thing. All done in Sutherland’s neat perspective mapping that he pioneered in the 1e “Survival Guides”.
But you what it hasn’t got? Catacombs. Nothing about them. Nada. The biggest word on the cover & title page, and as far as I can tell the word doesn’t even turn up in the text. Disappointing. That’s OK though; I have something in the works that will cover catacombs.
The other odd thing about this one is the annoying illustrations of a nerdy DM and his gaming group, which is so mocking as to be unsympathetic. It’s supposed to be comical but really comes off as pretty contemptuous.
I haven’t read any of the later editions’ Dungeon Master Guides so I can’t say how much of this was carried over to them — honestly I haven’t even read the 2e DMG in years so I don’t know if this redundant to stuff in there. It does give a very concise set of guidelines that you can use in any game, so it’s worth checking out for that and for the handful of maps in the back. For as much I hated most of the brown splatbooks of character options back in the day, this blue splatbook is surprisingly good.